Smelter operation

Sulfuric acid is the most important sulfur-containing intermediate product. More than 85% of the sulfur consumed in the world is either converted to sulfuric acid or produced direcdy as such (see Sulfuric acid and sulfur trioxide). Worldwide, well over half of the sulfuric acid is used in the manufacture of phosphatic fertilizers and ammonium sulfate for fertilizers. The sulfur source may be voluntary elemental, such as from the Frasch process recovered elemental from natural gas or petroleum or sulfur dioxide from smelter operations. 

Paper Products. Paper (qv) products account for about 2% of sulfur demand. The largest single segment of demand is in the manufacture of wood pulp by the sulfite process (see Pulp). In this process, the main sulfur intermediate is sulfur dioxide, which is generally produced at the plant site by burning elemental sulfur. Some sulfur dioxide, however, is produced as a by-product at smelter operations, purified andUquefied, and shipped to the pulp mills. The sulfur dioxide is converted to sulfurous acid, and the salt of this acid is a principal component of the cooking Hquor for the sulfite process. 

One establishment in a facility mines ore all of the ore is smelted at a second establishment in the facility. The facility could calculate the value of production for each establishment separately. Alternatively, the facility could determine the value of the smelter operation by subtracting the value of the ore produced from the value of entire facility s production. 

Five-Year History of a Biologically Based Treatment System that Treats High Concentrations of Effluent from an Industrial (Smelter Operation)... 

Sulphuric acid is the largest volume chemical in the world with an annual production of about 180 mill, t/year which is used primarily for phosphate fertilizers, petroleum alkylation, copper ore leaching and in smaller quantities for a number of other purposes (pulp and paper, other acids, aluminium, titanium dioxide, plastics, synthetic fibres, dyestuffs, sulphonation etc.). The major sulphur sources for sulphuric acid production are sulphur recovered from hydrocarbon processing in the refineries and from desulphurisation of natural gas, SO2 from metallurgical smelter operations, spent alkylation acid, and to a minor extent mined elemental sulphur and pyrites. A simplified flow sheet of a modem double-absorption plant for sulphuric acid production from sulphur is shown in Fig. 1. 

Ryan et al. (2001) studied the effects of hydroxyapatite addition to soils impacted by Pb from smelter operations. Dialysis experiment were conducted where the soil and hydroxyapatite solids were placed in separate dialysis bags suspended in 0.01 M NaN03. Chloropyromor-phite formed on the dialysis membrane containing the soil. The dissolution of solid-phase soil Pb was the rate-limiting step for pyromorphite formation. EXAFS showed that after the 240 day incubation the hydroxyapatite treatment caused a change in the average, local molecular bonding environment of soil Pb. 

Smelter Acid. If acid is produced involuntarily, as in a smelter operation, it is possible to estimate the cost of acid production in the same manner as that for an elemental sulfur acid plant. To the smelter, however, acid output is simply a mandated concomitant of the process required to produce the metal. Depending on the location of the smelter, the sources of demand, the size of the market, and competition from other producers, the acid sale price may or may not be sufficiently high even to yield a positive net-back, much less a desired rate of return on investment for the acid portion of the operation. This situation does not necessarily lead to closure. Positive or negative, the effect should be registered only in the overall profitability of the entire smelter operation. 

Air pollution is a well known problem, one that migrates across international boundaries. Chemists sampling the air in North America, for example, can detect heavy metals released by smelters operating in China. Chlorofluorocar-bons released in the Northern Hemisphere affect ozone levels in the air above the South Pole. Since the introduction of the internal-combustion engine, atmospheric carbon dioxide levels have been rising markedly, and global warming is a potential consequence. 

The approach taken to observe the impact of the copper smelter on mesoscale variations rainwater composition was to determine the spatial, temporal, and experimental components of the variability of a number of appropriate chemical species in the rainwater. This paper presents results for 1985, during smelter operation, and includes (1) estimates of the experimental variability in chemical composition, (2) an approach for a two step chemical and statistical screening of the data set, (3) the spatial variation in rainwater composition for a storm collected on February 14-15, and (4) a principal component analysis of the rainwater concentrations to help identify source factors influencing our samples. 

We have analyzed the rainwater chemical data with multivariate data analysis techniques to identify sources influencing the area covered by our sampling network. Two events were included in the principal component analysis (PCA) the February 15 storm presented here and another storm collected during smelter operation on March 20, 1985... 

Measurement of the experimental uncertainties in our rain sampling procedures and the application of these uncertainties in a screening procedure to eliminate questionable samples from the data set increases the confidence in the interpretation of spatial variations in rainwater composition and of the principal component analysis. Results presented here for a storm collected during smelter operation suggest that it was the major source of the downwind excess SO. elevation above background and the pH depress ion oelow the background value of 5. 

TABLE 12.7 Preabatement and Postabatement Atmospheric Fluoride Emission Rates in Primary Aluminum Smelters Operating in the U.S.A. and Canada"... 

FIGURE 13.9 Operating details of (a) a gravity settling chamber and (b) a section of a balloon-flue for removal of the coarser dusts from copper smelter operation. 

The cultivar seeds were sown in pots filled with contaminated soil prepared from the Warynski zinc smelter site. The Warynski smelter is located near the town of Piekary Slqskie and 15 km northwest of the major population center of Katowice [pop. 345,000] (Central Statistical Office, 1999). The site is owned by the Orzel Bialy Mining Metallurgical Works, S.A. and over 1.3 million people live within a 15 km radius of this site. Zinc and lead ore smelters operated at the site from 1927 until 1990. During this activity period, the smelters produced approximately 3,500,000 tons of mixed lead (Pb), cadmium (Cd) and zinc (Zn) waste, deposited in piles spread across a 60 hectare site. Although limited recyclable smelting activity continues at the site, the Piekary Slaskie municipal authorities are interested in redeveloping the land for alternative industrial purposes. 

A brief description of a typical copper smelter operation will help in understanding the extremely variable nature of the sulfur dioxide gas stream to be processed. The copper concentrates delivered to the smelter are a mixture of copper and iron sulfides. In current practice these are processed in two or three steps to produce 99% blister copper. In some smelters the concentrates are first partially roasted, removing 20-50% of the sulfur. This produces a relatively strong, steady gas stream containing 4-14% sulfur dioxide, depending on the type of roaster used. 

Discarded lead-acid batteries may be recycled by processing in conventional lead smelter operations, although the present trend is towards recycling battery wastes in dedicated facilities operated by the battery manufacturers themselves or by independent reprocessors. 

Of the primary operations which responded to the questionnaire, five are employing oxygen enrichment of the blast air. Nevertheless, none of the smelters operate with high oxygen enrichment and the degree of enrichment varies between 1.7% and 6.5%. 

Regardless of the choice of the procedure for refining the lead bullion, the first stage is dressing. This operation is normally performed as the last step of the smelting process and is integrated in the smelter operation and not in the refinery. Here the bullion is simply cooled in order to precipitate mainly copper and nickel. 

The Herculaneum smelter operates a 340-ton per day Monsanto type single contact acid plant on the site. This plant treats the sulfiir-rich gases produced in the sintering process. The 93% black sulfuric acid produced is stored in tanks on site. Sulfuric acid is shipped to customers from the smelter by truck, rail or river barge. The acid plant operates and performs maintenance on a schedule similar to the sinter plant. 

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